Upgrade Cisco 3750E IOS

First, configure an ip address at the switch so that it can communicate with tftp server

conf t

int vlan 1

ip address 192.168.0.254 255.255.255.0

• Backup old ios  copy flash:  tftp:   (please note, the file name is case sensitive. the source ios file can be at flash:/c3750e-universalkg-mz.122-44.SE2/c3750-universalk9-mz.122-44.SE2.bin, use sh flash: command to see first)
  

• Delete old ios files       delete  flash:c3750e-universalk9-mz.122-55.SE1.bin (old ios name)
  

or delete the old folder 

delete the old tar file (if there is one)wr

• Copy new ios bin file copy tftp: flash:

or  if you have tar file  use this command: archive tar /xtract tftp://192.168.0.2/c3750aaaaaa.tar flash:        (replace 192.168.0.2 with your tftp server ip address)

Set boot image

conf t

boot system flash:/c3750-advipservicesk9-mz.122-25.SEE1/c3750-advipservicesk9-mz.122-25.SEE1.bin

Exit

write memory 

• Confirm boot image  show boot
• reload